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Primaz you keep using the word "Normal" in your write up. With all due respect there is nothing "Normal" about your S Type. Shoe horning a massive V8 producing over 500 BHP, with four headers either side of the engine, under the bonnet of a 1960s S Type Jaguar is not "Normal" and a standard 1960s Jaguar with it's standard 200 plus BHP straight six driven sedately is not going to produce enough heat to melt plastic.
For a "Normal" 3.4 / 3.8 the original design is more than capable of handling the heat produced but there are minimal additions you can make to assist cooling. I go back to a well cleaned, well maintained engine. Heat wrap the exhaust manifolds to reduce heat in the engine bay. I have added an expansion tank which does not allow water and vapour to escape the system so my coolant levels are always correct. Add an external oil cooler in the front grill. Although I personally don't like them an extra Kenlowe fan on the front of the radiator to continue pushing air through the radiator on low revs and when the engine is turned off will remove hot air from the engine bay but will do minimal work to cool a shut off engine as the water pump is not circulating water through the radiator.
In SA's torrid conditions just an uprated/tropical radiator core is all that is needed. The uprated unit that Northampton Radiators build for Barretts is just fine and looks original. My thermostat keeps my engine up to temperature rather than the reverse of that ~ i.e. I'm overcooled. If required I would go direct to Northampton Radiators. These things are expensive from the traditional radiator suppliers like, Barratts, David Manners, Norman Motors etc. e.g. from Barratts £1,238.87 Inc Vat
This uprated radiator from Barratts that cost £500 in 2014 has Northampton Radiators plate on the lower tank ~ all brass.
Last edited by Glyn M Ruck; 12-03-2023 at 11:52 AM.
Primaz you keep using the word "Normal" in your write up. With all due respect there is nothing "Normal" about your S Type. Shoe horning a massive V8 producing over 500 BHP, with four headers either side of the engine, under the bonnet of a 1960s S Type Jaguar is not "Normal" and a standard 1960s Jaguar with it's standard 200 plus BHP straight six driven sedately is not going to produce enough heat to melt plastic.
For a "Normal" 3.4 / 3.8 the original design is more than capable of handling the heat produced but there are minimal additions you can make to assist cooling. I go back to a well cleaned, well maintained engine. Heat wrap the exhaust manifolds to reduce heat in the engine bay. I have added an expansion tank which does not allow water and vapour to escape the system so my coolant levels are always correct. Add an external oil cooler in the front grill. Although I personally don't like them an extra Kenlowe fan on the front of the radiator to continue pushing air through the radiator on low revs and when the engine is turned off will remove hot air from the engine bay but will do minimal work to cool a shut off engine as the water pump is not circulating water through the radiator.
Every car I have has increased power from a low of 50% to 700% and the shops I use have done a huge array of foreign/domestic, variety of engine swaps, performance upgrades, etc.; what I mean is that the Jaguar sedans are the only one with such a poor air flow out of the engine bay. That is what I mean by normal as I have personally modified many cars and my personal network is all made up of other performance enthusiasts and it is not normal to have such heat issues. Cars with way more heat with turbo's, etc. do not have the engine bay trap heat like the Jag. Part of it is such a small radiator opening and their design becomes more noticeable in today's faster pace, stop and go driving.
I do think having the exhaust manifold or headers coated are better than wrapping them but that is my personal view as I encountered more issues with metal fatigue with wraps. For a stock Jaguar what Glyn has done would be a good idea. A more robust radiator and better fan system would be the best first focus to me. Personally I think a good quality higher flow electric fan with a shroud tailed to the radiator is best so that all of that fan suction will force all of the air to go only thru the radiator and not have any air get bypassed would be ideal; you can also program them to keep running when the engine is off to help cool it down. On the latter if you were willing to open up the lower inner fender wells that would help the air get out of the engine bay, again due to the Jag engine bay trapping the air more than most other cars. Also what I have encountered is not much of an issue to cool the engine that is easy, it is the problem of air being stuck in the engine bay creating an oven like effect, thus if you have a better way to exhaust the air then when you run electric fans after the engine is turned off the air will get out better.
when making a fan more effective at pulling relatively cold air through the radiator with a form fitting shroud, it seems to me that it would make it just that much more difficult to keep the engine bay (the recipient of that extra hot air) cool. so i'm not sure that all i've read in this thread has convinced me.
in fact it appears that the problem, if indeed it is a problem, has a bit of "borrowing from Peter to pay Paul" in it. pulling more heat out the engine block coolant via efficient use of radiator and shroud, a task needed to cool an overly hot engine (Peter), simply transfers the problem to reducing the heat in an overly hot engine compartment (Paul). to do it right one would need to duct the heat coming out of the shroud directly out of the engine compartment. and i'm not hearing that in this thread. i hear a lot about ducting heat out of the engine compartment and a lot about efficiency WRT removing heat from the coolant. but each alone only serves to pass the heat down the line. or doesn't prevent it from getting in the line in the first place.
Last edited by hueyhoolihan; 12-03-2023 at 07:45 PM.
Hueyhoolihan, what you said would be ideal but given the very tight space in the engine bay you cannot duct it out but for me by opening up those triangular openings on both inner fender wells towards the rear of the engine bay it gives the air a way to escape. Most cars you would put a high quality radiator with mated shroud and there would be no issues, no need to wrap exhaust unless you are using a performance turbo, etc.
when making a fan more effective at pulling relatively cold air through the radiator with a form fitting shroud, it seems to me that it would make it just that much more difficult to keep the engine bay (the recipient of that extra hot air) cool. so i'm not sure that all i've read in this thread has convinced me.
in fact it appears that the problem, if indeed it is a problem, has a bit of "borrowing from Peter to pay Paul" in it. pulling more heat out the engine block coolant via efficient use of radiator and shroud, a task needed to cool an overly hot engine (Peter), simply transfers the problem to reducing the heat in an overly hot engine compartment (Paul). to do it right one would need to duct the heat coming out of the shroud directly out of the engine compartment. and i'm not hearing that in this thread. i hear a lot about ducting heat out of the engine compartment and a lot about efficiency WRT removing heat from the coolant. but each alone only serves to pass the heat down the line. or doesn't prevent it from getting in the line in the first place.
Huey, My problem in replying is that my relatively standard Mk2 never had either problem. That's in spite of me driving it hard on German and Italian motorways, over the Alps, and generally treating it like touring car champion that it is. However, the feature you mention is part of the design of many racing sports cars with a front radiator from the 1960s on: the air comes in through the nose, then the radiator, and out into the low pressure area on the top of the nose just back from the radiator. It's very visible on the Ford GT40. It wouldn't be difficult to arrange on one of our cars, but I don't imagine many of us want a big hole at the front of the bonnet just behind the leaper?
Surprisingly, no one has mentioned a front air dam with a scoop taking air up to the rad. It's there to some extent on every modern car and to a greater extent on saloon racers. It does the job of increasing flow through the radiator and out of the engine bay by lowering the pressure beneath it. It also improves the drag coefficient and, better still, on a Mk2 it would block the full frontal view of the front subframe. Glyn has a very nice photo of an aesthetically pleasing (in my opinion) example. Of course, it'll not do much at low speeds ... so don't drive slowly!
Air dams brings us to the Callum MK2. It also has those 'gills' in the wings, which I presume are connected to the engine bay. They should work to extract air as there's usually a low pressure area behind the wheels at speed and they can rely on some convection when not moving. For me, they don't look very nice. Better the triangular cut outs of the Austin-Healey rally cars. Still, I don't think I can bring myself to cut any sort of holes in the external wings (fenders). Apart from spoiling Sir William's lovely curves, think how much those panels retail!
I didn't dislike the rest of the front wing treatment of the Callum car. Sadly, the car might not have been the success it first seemed to be. I've seen nothing of the follow on examples CMC talked of building. The original car is listed by the licensing body DVLA as SORN, statutory off road = not in use, and is still registered as having its 3.8 engine rather than the upgrade. It sounds as if it's had little use and is close to abandoned.
Surprisingly, no one has mentioned a front air dam with a scoop taking air up to the rad. It's there to some extent on every modern car and to a greater extent on saloon racers. It does the job of increasing flow through the radiator and out of the engine bay by lowering the pressure beneath it. It also improves the drag coefficient and, better still, on a Mk2 it would block the full frontal view of the front subframe. Glyn has a very nice photo of an aesthetically pleasing (in my opinion) example. Of course, it'll not do much at low speeds ... so don't drive slowly!
Peter, that is exactly what I did add a lower front air dam out of aluminum but designed it as more of a scoop which then has a "V" to route the air around my V8. when you look head on the car you hardly even see it and it works. That is probably the best thing for all of these heat problems.
Primaz ~ In South Africa your car could not be registered as a Jaguar. They would Register it as a highly modified saloon. Punch out all Jaguar numbers with X's and punch a large new VIN Number on an inner fender or wherever and that would be that. That's what they did to my friend's car who now lives in Rockwall Northeast of Dallas & owns a Studebaker GT Hawk that is a mixture of 2 different years because he preferred the boot/trunk lid finish of one year (really just a trim panel) with the nose treatment of another & is fitted with a GM modded crate engine & transmission that GM had never done as a combo. So a highly credible shop North of Dallas had to build a bespoke electronic interface unit so that the transmission and engine could talk to one another. It has upgraded brakes, rear axle, suspension, Boyd Coddington bespoke wheels etc. etc. etc. If you floor the throttle it will burst into wheelspin in most gears. Needs to be driven by a sensible & capable driver or you could get into big trouble very easily. After I helped him sell his South African company for 1.3 billion Rand he has retired but bought a 50% share in a restoration shop in Poland & a classic car shop in Holland. He lives in a newly built travertine clad mansion with very clever architecture that hides a fully fledged 43 car garage. Mini Jay Leno of sorts, overlooking a lake. The whole house is driven from your smartphone.
BTW ~ it has dual shocks per side positioned in a fashion to stop axle tramp from the cart sprung rear end.
Last edited by Glyn M Ruck; 12-04-2023 at 05:04 AM.
Pete I agree and you keep hitting the head of the nail with your hammer. A Standard 1960s Jaguar does not have the problems that Primaz keeps talking about with his monstrous aberration. I like you would not want to cut holes anywhere on my S Type to allow non existent excessive hot air out of my engine bay. I have never had a problem even on the hottest UK day (Mid 30s) stop starting, driving in heavy traffic or stuck in a line of stationary traffic getting into a car show. Yes I have watched the temp gauge creep up above 70 degrees and worried but it has remained there never boiling the kettle. Once I have parked up at the show or home I open the bonnet and low, all the hot air rises as if it is a miracle, out of the engine bay and adds to global warming.
This gets me as well. A Kenlowe fan on the front of your radiator pushing air through the radiator to cool an engine that has been switched off. What exactly is it cooling other than the water in the radiator. The water in the block is not being circulated by the water pump so at best you will have some capillary action and any air being forced through the radiator by the fan is going to be heated by the radiator adding to the heat under the bonnet. The simplest solution is generally the best. Open your bonnet when you stop and let the hot air out.
Primaz ~ In South Africa your car could not be registered as a Jaguar. They would Register it as a highly modified saloon. Punch out all Jaguar numbers with X's and punch a large a new VIN Number on an inner fender or wherever and that would be that. That's what they did to my friend's car who now lives in Rockwall Northeast of Dallas & owns a Studebaker GT Hawk that is a mixture of 2 different years because he preferred the boot/trunk lid finish of one year (really just a trim panel) with the nose treatment of another & is fitted with a GM modded crate engine & transmission that GM had never done as a combo. So a highly credible shop North of Dallas had to build a bespoke electronic interface unit so that the transmission and engine could talk to one another. It has upgraded brakes, rear axle, suspension, Boyd Coddington bespoke wheels etc. etc. etc. If you floor the throttle it will burst into wheelspin in most gears. Needs to be driven by a sensible & capable driver or you could get into big trouble very easily. After I helped him sell his South African company for 1.3 billion Rand he has retired but bought a 50% share in a restoration shop in Poland & a classic car shop in Holland. He lives in a newly built travertine clad mansion with very clever architecture that hides a fully fledged 43 car garage. Mini Jay Leno of sorts, overlooking a lake. The whole house is driven from your smartphone.
Same in the UK Glyn. The DVLA would class it as a Radically Altered vehicle which would require re registering as such. The UK works on a points system and you need 8 to retain the registration. So if you use the original Body you get 5 points.2 for the original suspension both front and rear. 2 for the original axles front and rear. 2 for the original transmission. 2 for the original steering and 1 for the original engine.
Yes Cass ~ modern Mercedes cars fans keep running but they have an electric pump that keeps coolant circulating until temperatures have normalised after heat soak.
Yes Cass ~ modern Mercedes cars fans keep running but they have an electric pump that keeps coolant circulating until temperatures have normalised after heat soak.
The sort of processor required to monitor temperatures and control that sort of pump has been around for 40 years at least. That is, forty years ago someone put one together for me for a different application (actually to control a spark). It seemed like magic to me, but dead simple to the guys who put it together. Nowadays, probably any teenager can do it.
Absolutely Peter. It's not rocket science. Most modern cars with electric fans do it. Maybe a Morris Oxford Taxi from India not. Although even they have been improved under the bonnet.
Last edited by Glyn M Ruck; 12-04-2023 at 10:08 AM.
Peter, that is exactly what I did add a lower front air dam out of aluminum but designed it as more of a scoop which then has a "V" to route the air around my V8. when you look head on the car you hardly even see it and it works. That is probably the best thing for all of these heat problems.
I should probably do that for my cars, as I find these older Jaguars have terrible heat soak into the cabin on long drives. The engine may be running at normal temperatures, but after a long drive the interior is approaching the same temperatures, even with the windows open. I have routinely measured interior temps of 60°C in my S Type after driving it for 8 hours in the summer. It's actually a very unpleasant car to drive for any distance.
12-03-2023, 04:10 AM
